The subject matter disclosed herein relates to a seal apparatus and, more particularly, to a seal apparatus to restrict leakage flow.
In a turbine engine, such as a steam turbine engine, high energy fluids, such as steam, are directed through a turbine section where they aerodynamically interact with turbine buckets to cause turbine bucket rotation by which power and/or electricity may be generated. Thus, since the turbine bucket rotation is caused by the interaction of the high energy fluids and the turbine buckets, any leakage of the high energy fluids represents an efficiency cost in the power and/or electricity generation.
In some case, leakage of high energy fluids occurs through leakage flow paths defined between stationary components of the turbine engine. Zero clearance seals are, therefore, typically installed within these leakage flow paths to prevent or at least substantially restrict the high energy fluid leakage. Zero clearance seals are employed because they are formed to provide zero or nearly zero clearance between themselves and the stationary parts. In practice, however, even zero clearance seals may allow for the leakage of high energy fluids to occur due to errors associated with machining tolerances or thermal expansion of the seals.
Where zero clearance seals allow for the leakage of high energy fluids to occur, the leakage may be directed in either the axial dimension (i.e., along a longitudinal length of the turbine), the radial dimension (i.e., radially outwardly from the turbine) or both the axial and radial directions.